TGF-β1 is a neurotrophic factor that exerts neuroprotective effects against β-amyloid-induced neurodegeneration (Caraci et al., 2008), and a selective impairment of TGF-β1 signaling pathway has been demonstrated in the early phase of AD pathogenesis (Tesseur et al., 2006). The gene discussed is TGFB1; the disease is Alzheimer disease.